1. Technical Field
The invention relates to a polymer and more specifically to a modified conjugated diene based polymer.
2. Description of the Related Art
Conjugated diene polymer is widely used for resin modifying applications and various industrial goods. One of use is for manufacturing tires. Demand for low fuel consumption and attrition for the tires has increased with increasing environmental consciousness. To conform to the current demand trend, the rolling resistance property, the wet traction property, the tensile strength property, etc. of mechanical characteristics of the conjugated diene polymer must be increased.
Currently, carbon black is added to the conjugated diene polymer to increase the strength of the tires. In recent years, due to the depletion of oil resource and the global warming issue, the industries have many methods by using silica as a reinforcing filler. In comparison with carbon black, silica is more difficult to be uniformly distributed in conjugated diene polymer. Therefore, the compatibility between silica and conjugated diene polymer needs to be further increased.
According to one improvement method, when adding silica to the conjugated diene polymer during the manufacturing process of tires, a modifier of small molecule is used to perform blending. However, since the blending uniformity largely affects the properties of the products, product quality may differ from batch to batch, and quality reproducibility is poor. Moreover, it is hard to make sure if the conjugated diene polymer is modified by the modifier, or the modifier only reacts with silica.
In addition, compatibility between silica and a main chain modified conjugated diene based polymer can be increased by a main-chain modifying method. However, characteristic of the main chain modified conjugated diene based polymer is not stable during a long duration due to its saturated double bond on a molecular chain of which.
A prior reference EP0322166 discloses adding an antioxidant into a conjugated diene based polymer. It can improve slightly only discoloration or thermal decomposition problem occurring in a high temperature process of a blending step, etc. However, it can not solve the problem of the unstable characteristic of the main chain modified conjugated diene based polymer during a long duration. 2,4-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)-ethyl]-phenyl acrylate can be added into a raw glue of a rubber after stopping a polymerization reaction for the rubber or during a blending step to solve the discoloration or thermal decomposition problem that would occur in a subsequent high temperature process such as a blending step, etc. following the polymerization reaction.